The trial involved 4,000 people and its results have been called “remarkable” by medical experts, due in part because of the unprecedented speed in which the vaccine was developed.

“Having seen the devastating effects of Ebola on communities and even whole countries with my own eyes, I am very encouraged by today’s news,” said Børge Brende, the foreign minister of Norway, which helped fund the trial.“

“This new vaccine, if the results hold up, may be the silver bullet against Ebola, helping to bring the current outbreak to zero and to control future outbreaks of this kind,” he said on Friday.

The World Health Organization (WHO) said the vaccine could be a "game-changer".

This trial centred on the VSV-EBOV vaccine, which was started by the Public Health Agency of Canada and then developed by the pharmaceutical company Merck.

It combined a fragment of the Ebola virus with another safer virus in order to train the immune system to beat Ebola.

Scientists, doctors, donors and drug companies collaborated to race the vaccine through a process that usually takes more than a decade in just 12 months.

The unique clinical trial took place in Guinea, where when a patient was discovered, their friends, neighbours and family were vaccinated to create a "protective ring" of immunity.

One hundred patients were identified in the trial between April and July and then close contacts were either vaccinated immediately, or three weeks later.

Médecins sans Frontières (MSF), who were involved with the research, said: “When there is a new outbreak this vaccine will be put to use to stop the outbreak as soon as possible to not have the terrible disaster we have now."

More than 11,000 people have died from Ebola and nearly 28,000 have been infected.

The number of cases has fallen - and in the week up to July 26th 2015 there were just four cases in Guinea and three in Sierra Leone.